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1.
Makris NC Ratilal P Symonds DT Jagannathan S Lee S Nero RW 《Science (New York, N.Y.)》2006,311(5761):660-663
Until now, continental shelf environments have been monitored with highly localized line-transect methods from slow-moving research vessels. These methods significantly undersample fish populations in time and space, leaving an incomplete and ambiguous record of abundance and behavior. We show that fish populations in continental shelf environments can be instantaneously imaged over thousands of square kilometers and continuously monitored by a remote sensing technique in which the ocean acts as an acoustic waveguide. The technique has revealed the instantaneous horizontal structural characteristics and volatile short-term behavior of very large fish shoals, containing tens of millions of fish and stretching for many kilometers. 相似文献
2.
Development and evaluation of a rapid absorbed enzyme immunoassay test for the diagnosis of Johne''s disease in cattle 总被引:8,自引:0,他引:8
An absorbed enzyme immunoassay (EIA) test for Johne's disease in cattle was developed in which absorption of cross-reacting antibodies occurred as a rapid reaction in solution rather than overnight with whole organisms and a subsequent centrifugation step. Total test time was reduced to less than 2 h with a minimum of manipulations. The test was evaluated in cattle herds from Johne's disease-endemic and Johne's disease-free regions of Australia. Specificity was 99.8%. Calculations of sensitivity were affected by the history of the herd under test. However, the EIA detected in excess of 80% of animals before onset of clinical disease and 65% of faecal shedders were EIA positive on, or before, first detection of Mycobacterium paratuberculosis in their faeces. The test should aid epidemiological studies and be a useful tool in the management and control of Johne's disease. 相似文献
3.
Measurements of electrical conductivity at high pressure and temperature were taken on the lower mantle phase magnesiowustite with varying Fe3+ content. Although previous measurements at atmospheric pressure suggest Fe2+-Fe3+ hopping (small polaron) as the dominant conductivity mechanism, the present experiments show a change in charge transport mechanism with temperature. The lower temperature measurements are consistent with small polaron conduction, but at higher temperatures, which are more applicable to the lower mantle, a large polaron mechanism is suggested. Because these mechanisms have different temperature and compositional dependencies, this transition has important implications for extrapolation to mantle conditions. 相似文献
4.
DH Lowndes DB Geohegan AA Puretzky DP Norton CM Rouleau 《Science (New York, N.Y.)》1996,273(5277):898-903
Pulsed laser deposition (PLD) is a conceptually and experimentally simple yet highly versatile tool for thin-film and multilayer research. Its advantages for the film growth of oxides and other chemically complex materials include stoichiometric transfer, growth from an energetic beam, reactive deposition, and inherent simplicity for the growth of multilayered structures. With the use of PLD, artificially layered materials and metastable phases have been created and their properties varied by control of the layer thicknesses. In situ monitoring techniques have provided information about the role of energetic species in the formation of ultrahard phases and in the doping of semiconductors. Cluster-assembled nanocrystalline and composite films offer opportunities to control and produce new combinations of properties with PLD. 相似文献
5.
AIMS: To assess the sensitivity and specificity of a bulk tank milk (BTM) antibody enzyme-linked immunosorbent assay (ELISA) to detect likely infection of a dairy herd with bovine vi- ral diarrhoea virus (BVDV). The ELISA was subsequently used to estimate the prevalence of likely infected herds in parts of the North Island of New Zealand. METHODS: BTM samples from 724 randomly selected dairy herds in the Waikato, Bay of Plenty and Northland regions of New Zealand were tested for BVDV antibodies. From this group, 20 herds were again randomly selected from each of the quartiles of the ELISA percentage inhibition (%INH) result. From each participant herd, serum from 15 randomly selected calves aged 6–18 months and 15 cows was collected and tested using an indirect blocking ELISA for BVDV antibodies. RESULTS: Among serum results from calves from 50 herds available for analysis, 34 (68%) herds were classified as likely non-infected (0-3 seropositive among 15 calves) and 16 (32%) as likely infected (5–15 seropositive among 15 calves). Receiver- operator characteristic (ROC) analysis identified an optimal cut-off for BTM of 80%INH associated with 81% sensitivity and 91% specificity for likely herd infection. The prevalence of BVDV antibodies in cows within herds and %INH for BVDV in bulk milk were positively correlated (p<0.01). The association between bulk milk %INH and the prevalence of BVDV antibodies in calves was stronger than the same association in cows. Based on the threshold of 80%INH, the 95% confidence interval (CI) for prevalence of likely infection in the 724 herds in the Waikato, Bay of Plenty and Northland regions of New Zealand was 12–17%. Vaccination against BVDV was not significantly associated with the likely infection status of the herd based on prevalence of BVDV antibodies among calves. CONCLUSION: An ELISA test result for BVDV antibodies in BTM ≥80%INH can be used as a threshold to indicate the presence of likely infection with BVDV in dairy herds in New Zealand, with 81% sensitivity and 91% specificity. 相似文献
6.
PB Fernandes KO Marques FR de Araujo Neto DP de Oliveira NA Hurtado‐Lugo RR Aspilcueta‐Borquis H Tonhati 《Reproduction in domestic animals》2016,51(3):428-434
Because of the importance of reproduction in stock breeding systems, it is necessary to find selection criteria that increase reproductive efficiency. The aim of this study was to estimate genetic parameters for the probability of conception on first service (PROB) in Murrah heifers, and its association with other traits of economic interest [age at first calving (AFC), service period, calving interval and milk yield at 270 days], with the purpose of evaluating their use as selection criteria. Reproductive information and first lactation records of 1200 Murrah heifers were used to perform two‐trait analyses between PROB and the other characteristics. Bayesian inference was used to estimate the variance components, considering PROB as threshold and the other as linear factors. The results demonstrate that this trait has heritability of 0.15, indicating the possibility of a genetic gain by using it for selection. With respect to the genetic correlation estimates, the only high‐magnitude association was with AFC (?0.899), which is the current criterion indicating sexual precocity of females. In the light of the parameters estimated, the first‐service pregnancy rate is an alternative for indication of sexual precocity, although presenting a smaller genetic gain than the current standard AFC. Nevertheless, additional research should be conducted regarding this trait to assess the economic importance of its use in dairy buffalo production systems. 相似文献
7.
Background
The Resource Dispersion Hypothesis (RDH) proposes a mechanism for the passive formation of social groups where resources are dispersed, even in the absence of any benefits of group living per se. Despite supportive modelling, it lacks empirical testing. The RDH predicts that, rather than Territory Size (TS) increasing monotonically with Group Size (GS) to account for increasing metabolic needs, TS is constrained by the dispersion of resource patches, whereas GS is independently limited by their richness. We conducted multiple-year tests of these predictions using data from the long-term study of badgers Meles meles in Wytham Woods, England. The study has long failed to identify direct benefits from group living and, consequently, alternative explanations for their large group sizes have been sought. 相似文献8.
João CA. Alves Ana MMP. dos Santos Ângelo DP. Fernandes 《Veterinary anaesthesia and analgesia》2018,45(1):123-128
Objective
To evaluate the feasibility and effectiveness of mesotherapy in dogs compared with a positive control group.Study design
Experimental, randomized, blinded study.Animals
Fifteen working police dogs with chronic back pain.Methods
Animals were divided randomly into control (CG; n = 5) and treatment groups (TG; n = 10). A combination of 140 mg lidocaine, 15 mg dexamethasone and 20 mg thiocolchicoside was administered to group TG along with a 70-day course of a placebo, administered as if it was carprofen. Carprofen was administered to Group CG for 70 days, at a dose adjusted to their weight. On day 0, an intradermal injection of Ringer’s lactate was also administered. Both groups were rested for 3 days and resumed normal activity over a 5-day period. Response to treatment, measured by the Canine Brief Pain Inventory (CBPI) and the Hudson Visual Analogue Scale (HVAS), was evaluated before treatment (T0), after 15 days (T1) and 1 (T2), 2 (T3), 3 (T4), 4 (T5) and 5 (T6) months. Results were compared using a Mann–Whitney test or a paired samples t test.Results
When comparing CBPI results, no differences were found between groups TG and CG at T0 through T3 and in T6 and T7. Differences were observed in CBPI sections after the discontinuation of carprofen: at T4 [p = 0.02 for Pain Interference Score (PIS) and p = 0.03 for Pain Severity Score (PSS)] and T5 (p = 0.16 for PIS and p = 0.03 for PSS), with group TG having overall better results. Individual treatment results were considered successful in one dog of group CG (20%), whereas in group TG, success was higher (ranging from 78% at T1 to 22% at T7). No significant differences were registered with the HVAS.Conclusions and clinical relevance
Mesotherapy may be a promising treatment option for canine musculoskeletal-related pain. Further studies are required. 相似文献9.
For reasons of examining any possible discrimination of young red wines based on selected, minor polyphenols, a survey was carried out including 35 samples originating from three Hellenic native and three international Vitis vinifera cultivars from various regions of Greece. All samples were experimental wines vinified and stored under identical conditions, in an effort to minimize the effect of different winemaking technologies as well as aging. The polyphenols analyzed belonged to two categories: benzoic acid derivatives, including gallic acid, protocatechuic acid, vanillic acid, and syringic acid, and stilbenes, including astringin, piceid, and resveratrol (all trans isomers). Data handling employing discriminant analysis (DA) yielded very satisfactory categorization of samples in terms of both cultivar and geographical region of origin. This outcome was discussed with regard to the value of certain minor polyphenols that could serve as characteristic indices for discrimination of varietal red wines, after appropriate implementation of chemometrics. 相似文献
10.